Building up of machine tools, specially grinding machines



May 16, 1933. c. KRUG 1,909,110

BUILDING UP OF MACHINE TOOLS, SPECIALLY GRINDING MACHINES Filed Oct. 29,1928 :s Sheets-Sheet .1

1- I O a 0 47 44\== h 15 g 42 46 46%- May 16, 1933. c. KRUG BUILDING UPOF MACHINE TOOLS, SPECIALLY GRINDING MACHINES Filed Oct. 29. 1928 sSheets-Sheet 2 May 16, 1933. c KRUG 1,909,110

BUILDING UP OF MACHINE TOOLS, SPECIALLI GRINDING MACHINES Filed Oct. 29,1928 3 Sheets-Sheet 3 Patented May 16, 1933 UNITED STATES CARL KRU'G, OFFRANKFORT-ON-THE-MAIN, GERMANY BUILDING U]? OF MACHINE Toots, SPECIALLYGRINDING MACHINES Application filed October 29, 1928, Serial No.315,902, and in Germany October 26, 1927.

The main building elements of machine tools, as foundations, frames,under frames, standards, uprights, arms, tables or the like, arepreferably cast of iron. The quantity of material used for this purposeis quite out of proportion to what would be necessary on account of thestresses to which these elements are submitted or of the admissiblealteration of shape. Foundry technical reasons and the consideration ofthe treatment make it generally necessary to increase to a multiple thequantity of material which would be absolutely necessary for fulfillingthe technical purpose of the machine tool.

The reason for the almost exclusive use of cast iron is the simplicitywith which by the casting process even the most complicated forms can beobtained.

By the modern development of the weldingtechnics the possibility ofusing building materials possessing higher resistance and which are notmoulded by casting process h s been thoroughly altered.

'This invention has for its object to do away with the utilization ofcast iron preferably in order to reduce the cost of manufacture of themachines and to improve the machines with the aid of the weldingtechnics which have only quite recently de 0 veloped to perfectness andeconomy. It has already been proposed to build certain parts of drivingengines, like casings of dynamos or foundation frames for the same fromingot steel sheets, but it has never been proposed to intentionallytransform the existing types of machine tools so that it becomespossible and remunerative to use building.

bodies of steel for the several elements. One has, of course, to countwith the increased expenses for the welding but these expenses are morethan compensated b savings in expenses. for transport, simpli edworking, suppression of the expenses for models, cheaper machines andserious reduction of storing expenses and general expenses, not tomention the advantage of being no longer .dependent on the foundries andthe saving of time as no models have to be made. It is howeverimpossible to substitute simply wrought iron and ingot steel for thecast iron and to merely alter the cross sections in .the relation 1 by2, 5, i. e. in the proportion of the modulus of elasticity of thesematerials. The use of wrought iron and steel and the utilization of thewelding technics require new peculiar forms. Specially disappear thegradual transitions at alterations of cross section peculiar to thecasting process and the local accumulations of material, and in generalall expenditures in material which are not absolutely required by theabsolutely necessary degree of resistance and limitation of alterationof shape. A principal difficulty is the mounting of guide faces formoving machine elements. This difiiculty is overcome according to theinvention in that the connection elements with guide faces in completelyfinished state are detachably, adjustably and readjustably connected,with interposition of an intermed-- iate element distributing andtransmitting pressure, to the hollow or frame bodies made of wroughtiron, ingot iron or ingot steel sheet plates or webs by means of weldings. This requires the solution of several secondary problems for themachine elements with plane guide faces. These problems are evidentlyother than for elements which possess rounded guide faces, like roundbearings, bushes or the like. Building elements with simple fittedblock-sup porting-or carrying surfaces are also joined in completelyfinished state, the adjustability and re-adjustability being howevergenerally omitted, v

It might be apprehended that the natu-- ral vibrations of the frames andof their elements, which are specially dreaded in the building ofgrinding machines, could not be securely avoided whenthese frames and 9I their elements are made ofthin rolled sheet metal plates. Calculationshows however that in preserving the same rigidity the natural vibrationcoeflicients remain the same. As with a very little consumption of 5material the natural vibration coefiicients can be takenconsiderablyhigher by increasing the degree of compactness of the several buildingelements, for instance'by insertion of intermediate transverse bars, thenew manner of building produces considerably greater rigidity andresistance against pre3- udicial vibrations than hitherto.

The advantages of the new building meth- 5 0d are considerable:extraordinary savings in wa es, in expenses for material and power, ligt machines and consequently low cost for transport and little loading ofceilings, greater rigidity and resistance against vibrations, littlelosses from friction and power in the moved building elements,possibility of carrying out more rapidly, andshorter terms for delivery,cheaper machine installations, less space required for themanufacturing, suppression of the inaccuracies and of the re-fashioningowing to warping at the ageing of the cast, suppression of expensivemodels, of the expenses for storing, and of the high insurance premiumsdue to the liability of the models to catch fire, less expensivemaintainance, possibilities to rap idly alter the shape, greatersecurity against breaking in transport, unsensitiveness against roughtreatment, greater accuracy in the long run, owing to there-a-djustability of the guide faces, simplest possibility of using themost favorable material pair: steel and cast iron for guide faces,possibility of building experimental machines and special machines inthe shortest delay Without loss of time and without manufacturing ofexpensive models which, if not satisfactory, are without value,possibility of using standard building elements like track plates, webs,arllxgle pieces, sliding face elements or the li e.

For grinding machines the new building manner is especially advisablefor the reason that the warping of the cast pieces owing to ageing isvery prejudicial to the high degrees of accuracy of the grindingmachines at the construction of the same as well as in service. Thepossibility of readjusting the guide faces is of decisive importance forthe preservation of the initial high degree of accuracy of the machines,and it is especially important for eventual breaking of the grindingtools that brittle materials like cast iron be avoided. Just in thegrinding machines the disparity between the actual consumption ofmaterial and that which would be necessary to fulfill the technicalpurpose, is very conspicuous. One needs only compare the dimensions ofthe small grinding wheels with the disproportionate shape of the wholemachine.

This is why a machine tool of the class of grinding machines has beenselected as example of the application of the invention.

In the accompanying drawings a surface grinding machine of the form ofconstruction which has become known by the main German Patent No.399,144 is shown in the 65 Figs. 1 to 10.

screw connections.

Fig. 1 is a front elevation showing the grinding machine.

Fig. 2 is a section through the machine.

Fig. 3 shows in elevation partly in section the underframe for thegrinding wheel spindle head stock.

Fig. 4 shows in section the bed and the table.

Figs. 5, 6 and 7 illustrate how building eliements with plane guidefaces are mounte Figs. 8 and 9 illustrate the mounting of a buildingelement with round guide surface, i. e. the bearing for the grindingwheel spindle shaft.

In Figs. 1 and 2, 1 designates the slide with the grinding wheel spindle2, which carries the main driving-disc 3, the driving disc 4 for thepump and the grinding tool 5.

The slide 1 for the grinding wheel spindle is shiftably arranged on theunderframe 6 and the table 7 is shiftably arranged on the bed 8, theunderframe and bed having on the walls facing each other projections 9ending in parallel vertical planes and adapted to be connected with eachother by Between them a clamping and adjusting device 10 is arrangedenabling the spacing of the free ends of the uprights. The table 7 isconnected with a piston movable in a cylinder 11 'fixed on the bed 8. Inthis cylinder end the conduits 12 and 13 for the pressure oil flowing inand out, the regulating of which is eifected by the piston slide 14 towhich the pressure oil is supplied by a pfessure pump arranged in themachine. The grinding wheel spindle slide 1 and the correspondingunderframe 6, the table 7 and the bed 8 are four main building elementsof complicated shape, which hitherto have been made of cast iron.According to theinvention they are composed of correspondingly cutplates of wrought iron or ingot steel and connected with each other bywelding, so that preponderantly hollow bodies or cells are producedwhich are preferably limited by right angles. The hollow bodies arestayed in the interior by horizontal and vertical partitions, supportingangle irons, webs and the like, which are connected with the main bodyby welding. In the figures the outer plates 15 are united with the innerplates 16, which may be of different shapes and dimensions, to formhollow bodies or cells. It is also possible that an inner plate extendsthrough the outer plates and becomes itself an outer plate 17. Theconnection of the several plates is effected by butt welding, byoverlapping or by attaching by means of several welding points,according to requirement .and accessibility of the welding points. Forconnecting two plates a third element, for instance an angle iron 18,may be. used, which is connected with the two plates by welding.

justed and re-adjusted. Figs. 5 and 6 illustratc in elevation andsection details of the point at which the guide rod is connected to themain body.

In building elements, which serve exclusively for a fitting, there-adjusting device may be suppressed, so that the finished fitted blockis connected to the main body merely by fixation screws, eventually withthe aid of intermediate elements. Under circumstances a readjustingdevice may be preferably provided. This will be the case if the mutualposition of two main building elements, for instance of the underframes6 and of the bed 8, has to be corrected (Fig. 3

In Figs. 8 and 9 is 2 the grinding wheel spindle with its bearing, whichconsists of a roller bearing 27 and a double thrust bearing 28 mountedin the common casing 29. This casing 29 is sunk in the bearing head 30of the machine, which consists of wrought iron or steel sheet plates 16cut accordingly and welded together, and it is fixed in the casing bymeans of screws 31 and pressure elements 32. The shafts of the screws 31move with clearance in the corresponding holes of the bearing head sothat the casing together with the shajft can be adjusted parallel to theaxis of the grinding wheel spindle by little amounts required for theadjusting and then secured in the adjusted position. In the flange ofthe bearing casing a set of adjusting screws 33 is further arranged, bywhich the angle to the axis of the grinding wheel spindle and to theaxis of the bearing head may be altered by little amounts necessary forthe adjusting.

-I claim 1. As an article of manufacture a frame of grinding machinesbuilt up of a multiplicity of cells formed of rolled sheet metal andwelded together preferably by spot welding in combination with machinetool slide ways having fitted and guide faces joined to the frame infinished state in order to improve the possibility of working.

2. As an article of manufacture a frame of grinding machines built up ofa multiplicity of cells formed of rolled sheet metal and welded togetherpreferably by spot welding in combination with machine tool slide wayshaving fitted and guide faces joined adjustabl and re-adjustably to theframe in finishe state.

3. As an article of manufacture a. frame of grinding machines built upof a multiplicity of cells the walls of which are erected of rolled thinsheet metal not exceeding 5 mms in thickness and preferably weldedtogether by spot welding in order to obtain the highest possiblerigidity with the minimum amount of material.

4. As an article of manufacture, a frame of grinding machines built upexclusively of thin sheet metal plates of equal thickness throughout,forming a multiplicity of cells welded together by s ot-welding.

In testimony whereof I a x my signature.

' CARL KRUG.

